package cn.fancylab.template.util;

/**
 * Byte 工具类
 * 
 * @author pixiaozhi
 */
public class ByteUtil {
	public final static byte[] EMPTY_BYTES = new byte[0];

	/*
	 * CCITT标准CRC16(1021)余数表 CRC16-CCITT ISO HDLC, ITU X.25, x16+x12+x5+1 多项式 高位在先时生成多项式 Gm=0x11021 低位在先时生成多项式，Gm=0x8408
	 * 本例采用高位在先
	 */
	private static int CRC16_CCITT_TABLE[] = { 0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf, //
			0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7, //
			0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e, //
			0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876, //
			0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd, //
			0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5, //
			0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c, //
			0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974, //
			0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb, //
			0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3, //
			0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a, //
			0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72, //
			0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9, //
			0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1, //
			0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738, //
			0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70, //
			0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7, //
			0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff, //
			0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036, //
			0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e, //
			0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5, //
			0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd, //
			0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134, //
			0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c, //
			0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3, //
			0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb, //
			0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232, //
			0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a, //
			0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1, //
			0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9, //
			0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330, //
			0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78 //
	};

	/**
	 * byte -> hex
	 * 
	 * @param b byte src
	 * @return Hex's String
	 */
	public static String toHex(byte b) {
		StringBuffer sw = new StringBuffer(2);

		sw.append(toHexDigit(b >> 4 & 0x0f));
		sw.append(toHexDigit(b & 0x0f));

		return sw.toString();
	}

	/**
	 * byte[] -> hex
	 * 
	 * @param bytes byte array src
	 * @return Hex's String
	 */
	public static String toHex(byte... bytes) {
		if (bytes == null)
			return "";

		int len = bytes.length;
		StringBuffer sw = new StringBuffer(len * 2);
		for (int i = 0; i < len; ++i) {
			sw.append(toHexDigit(bytes[i] >> 4 & 0x0f));
			sw.append(toHexDigit(bytes[i] & 0x0f));
		}
		return sw.toString();
	}

	/**
	 * int -> hex
	 * 
	 * @param i int src
	 * @return Hex's String
	 */
	public static String toHex(int i) {
		return Integer.toHexString(i);
	}

	/**
	 * int -> hex (指定长度)
	 * 
	 * @param i int src
	 * @param bs return bytes length
	 * @return Hex's String
	 */
	public static String toHex(int i, int bs) {
		final String hex = toHex(i);

		final int allLen = bs * 2;
		final int strLen = hex.length();

		if (strLen < allLen) {
			int padLen = allLen - strLen;

			StringBuilder sb = new StringBuilder();

			while ((padLen--) > 0) {
				sb.append('0');
			}

			sb.append(hex);

			return sb.toString();
		} else {
			return hex;
		}
	}

	/**
	 * HEX 优化，默认长度为2的倍数
	 * 
	 * @param hex String's Src
	 * @return Hex's String
	 */
	public static String toHex(String hex) {
		if (hex == null || hex.isEmpty()) {
			return "";
		} else if (hex.length() % 2 == 1) {
			return "0" + hex;
		} else {
			return hex;
		}
	}

	/**
	 * hex -> byte[]
	 * 
	 * @param hex hex's string
	 * @return bytes
	 */
	public static byte[] toByte(String hex) {
		if (hex == null || hex.length() == 0) {
			return EMPTY_BYTES;
		} else {
			char[] cs = hex.toCharArray();
			byte[] bs = new byte[cs.length / 2 + cs.length % 2];

			for (int i = 0; i < bs.length; i++) {
				int i1 = 0x00; // 高字节
				int i2 = 0x00; // 低字节

				if (cs.length % 2 == 1) {
					// 如果传入的hex长度为单数，默认前面添0
					if (i == 0) {
						i1 = toByteDigit('0') & 0x0f;
						i2 = toByteDigit(cs[i]) & 0x0f;
					} else {
						i1 = toByteDigit(cs[i * 2 - 1]) & 0x0f;
						i2 = toByteDigit(cs[i * 2 - 0]) & 0x0f;
					}
				} else {
					i1 = toByteDigit(cs[i * 2 + 0]) & 0x0f;
					i2 = toByteDigit(cs[i * 2 + 1]) & 0x0f;
				}

				bs[i] = (byte) (i1 << 4 | i2);
			}

			return bs;
		}
	}

	/**
	 * hex -> byte[] (指定byte数组长度)
	 * 
	 * @param hex hex's string
	 * @param length return byte array length
	 * @return bytes
	 */
	public static byte[] toByte(String hex, int length) {
		if (hex == null || hex.length() == 0) {
			return EMPTY_BYTES;
		} else {
			final int allLen = length * 2;
			final int strLen = hex.length();

			if (strLen < allLen) {
				int padLen = allLen - strLen;

				StringBuilder sb = new StringBuilder();

				while ((padLen--) > 0) {
					sb.append('0');
				}

				sb.append(hex);

				return toByte(sb.toString());
			} else if (strLen > allLen) {
				return toByte(hex.substring((strLen - allLen), strLen));
			} else {
				return toByte(hex);
			}
		}
	}

	/**
	 * int -> byte[]
	 * 
	 * @param i int src
	 * @return bytes
	 */
	public static byte[] toByte(int i) {
		return new byte[] { (byte) i };
	}

	/**
	 * int -> byte[] (指定byte数组长度)
	 * 
	 * @param i int src
	 * @param bs byte array length
	 * @return bytes
	 */
	public static byte[] toByte(int i, int bs) {
		byte[] result = new byte[bs];

		for (int j = 0; j < bs; j++) {
			result[bs - j - 1] = (byte) ((i >> (j * 8)) & 0xff);
		}

		return result;
	}

	/**
	 * byte -> int
	 * 
	 * @param b byte src
	 * @return int
	 */
	public static int toInt(byte b) {
		return b & 0xff;
	}

	/**
	 * byte[] -> int
	 * 
	 * @param bs bytes
	 * @return int
	 */
	public static int toInt(byte... bs) {
		int result = 0x00000000;

		for (int i = 0; i < bs.length; i++) {
			result = (result << 8) | (bs[i] & 0xff);
		}

		return result;
	}

	/**
	 * byte[] -> float
	 * 
	 * @param bs bytes
	 * @return float
	 */
	public static float toFloat(byte... bs) {
		int result = 0x00000000;

		for (int i = 0; i < bs.length; i++) {
			result = (result << 8) | (bs[i] & 0xff);
		}

		return Float.intBitsToFloat(result);
	}

	/**
	 * byte 数组转 Ascii
	 * 
	 * @param bs bytes
	 * @return ascii string
	 */
	public static String toAscii(byte... bs) {
		if (bs == null) {
			return null;
		} else {
			char[] cs = new char[bs.length];

			for (int i = 0; i < bs.length; i++) {
				cs[i] = (char) bs[i];
			}

			return new String(cs);
		}
	}

	/**
	 * hex -> int
	 * 
	 * @param hex hex's string
	 * @return int
	 */
	public static int toInt(String hex) {
		if (hex == null || hex.isEmpty())
			return 0;

		char[] cs = hex.toCharArray();

		int res = 0;
		int len = cs.length;
		for (int i = 0; i < len; i++) {
			res = res | ((toByteDigit(cs[i]) & 0x0f) << ((len - i - 1) * 4));
		}

		return res;
	}

	/**
	 * CRC生成
	 * 
	 * @param regInit reg init value
	 * @param bytes bytes
	 * @return crc's int
	 */
	public static int toCRC(int regInit, byte[] bytes) {
		int crcReg = regInit;
		for (int i = 0; i < bytes.length; i++) {
			crcReg = (crcReg >> 8) ^ CRC16_CCITT_TABLE[(crcReg ^ bytes[i]) & 0xff];
		}
		return crcReg;
	}

	/**
	 * CRC生成 （return byte[]）
	 * 
	 * @param bytes bytes
	 * @return crc's bytes
	 */
	public static byte[] toCRC(byte[] bytes) {
		int crc = toCRC(0x0000, bytes);

		byte b1 = (byte) ((crc >> 8) & 0xFF);
		byte b2 = (byte) (crc & 0xFF);

		return new byte[] { b1, b2 };
	}

	/**
	 * CRC（Xmodem） 生成
	 * 
	 * @param bytes bytes src
	 * @return crc's int
	 */
	public static int toCRCXmodem(byte[] bytes) {
		int crc = 0x0000;
		int polynomial = 0x1021;
		for (byte b : bytes) {
			for (int i = 0; i < 8; i++) {
				boolean bit = ((b >> (7 - i) & 1) == 1);
				boolean c15 = ((crc >> 15 & 1) == 1);

				crc <<= 1;
				if (c15 ^ bit)
					crc ^= polynomial;
			}
		}
		return (crc & 0xffff);
	}

	/**
	 * 转换二进制字符串
	 * 
	 * @param bs bytes src
	 * @return binary's string
	 */
	public static String toBinary(byte... bs) {
		StringBuilder builder = new StringBuilder();

		for (byte b : bs) {
			builder.append(b >> 7 & 0x01);
			builder.append(b >> 6 & 0x01);
			builder.append(b >> 5 & 0x01);
			builder.append(b >> 4 & 0x01);
			builder.append(b >> 3 & 0x01);
			builder.append(b >> 2 & 0x01);
			builder.append(b >> 1 & 0x01);
			builder.append(b & 0x01);
		}

		return builder.toString();
	}

	/**
	 * 获取HEX 的字节长度
	 * 
	 * @param hex hex's string
	 * @return hes's length
	 */
	public static int length(String hex) {
		if (hex == null)
			return 0;
		int len = hex.length();

		if (len % 2 == 0) {
			return len / 2;
		} else {
			return len / 2 + 1;
		}
	}

	private static char toHexDigit(int i) {
		if (i <= 9) {
			return (char) (i + 0x30);
		} else {
			return (char) (i + 0x57);
		}
	}

	private static int toByteDigit(char c1) {
		if (c1 >= '0' && c1 <= '9') {
			return (c1 - 0x30);
		} else if (c1 >= 'A' && c1 <= 'Z') {
			return (c1 - 0x27);
		} else if (c1 >= 'a' && c1 <= 'z') {
			return (c1 - 0x57);
		} else {
			return 0;
		}
	}
}